Annotates functions returning retained objects.

ios/web/net/clients/crw_js_injection_network_client_unittest.mm

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ios/web/net/clients/crw_js_injection_network_client.h"
 
 #import <Foundation/Foundation.h>
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
@@ skipping 93 matching lines @@
     test_data_.reset([[NSData dataWithContentsOfFile:
         base::SysUTF8ToNSString(file_path.value())] retain]);
     ASSERT_TRUE(test_data_);
   }
 
   void TearDown() override { EXPECT_OCMOCK_VERIFY(mock_web_proxy_); }
 
  protected:
   // Returns a CRNHTTPURLResponse. If |include_content_length|, header includes
   // Content-Length set to the length of test_data_.
-  CRNHTTPURLResponse* CreateTestResponse(BOOL include_content_length);
+  CRNHTTPURLResponse* CreateTestResponse(BOOL include_content_length)
+      NS_RETURNS_RETAINED;
 
   // Returns number of times an injected cr_web script tag is found in the
   // underlying client's loaded data. Script tag should immediately follow
   // the html start tag, if it exists, or should be injected before any header,
   // if the first tag is something other than an html start tag.
   NSUInteger GetScriptTagCount() const;
 
   // Checks that if response forwarded to the underlying client has header field
   // Content-Length, the value matches the length of the data.
   void ExpectConsistentContentLength();
 
   base::scoped_nsobject<CRWJSInjectionNetworkClient> js_injection_client_;
   base::scoped_nsobject<UnderlyingClient> underlying_client_;
   base::scoped_nsobject<OCMockObject> mock_web_proxy_;
   base::scoped_nsobject<NSData> test_data_;
 };
 
 CRNHTTPURLResponse* CRWJSInjectionNetworkClientTest::CreateTestResponse(
-    BOOL include_content_length) {
+    BOOL include_content_length) NS_RETURNS_RETAINED {

[Eugene But (OOO till 7-30), 2016/08/16 16:45:48]

Is it necessary to annotate in both interface and implementation?

[stkhapugin, 2016/08/16 16:51:49]

Actually this annotation only makes a difference in headers (as it only changes
behavior across arc/mrr boundaries), but we don't really have any guideline for
this, so I marked the ones in implementation files as well. 

[Eugene But (OOO till 7-30), 2016/08/16 17:02:31]

If |NS_RETURNS_RETAINED| in implementation does not add any value (and seems
like it does not) I think we should not clutter our code with unnecessary stuff.
Do you see any good reason for adding these annotations (except that Style Guide
is silent on this)?

   NSMutableDictionary *headers = [NSMutableDictionary
       dictionaryWithDictionary:@{ @"Content-Type" : @"text/html" }];
   if (include_content_length) {
     headers[@"Content-Length"] = @([test_data_ length]).stringValue;
   }
   return [[CRNHTTPURLResponse alloc]
       initWithURL:[NSURL URLWithString:@"http://testjsinjection.html"]
        statusCode:200
       HTTPVersion:@"HTTP/1.1"
      headerFields:headers];
@@ skipping 135 matching lines @@
   // Load data one byte at a time.
   for (NSUInteger i = 0; i < [test_data_ length]; i++) {
     [js_injection_client_ didLoadData:
         [test_data_ subdataWithRange:NSMakeRange(i, 1u)]];
   }
   [js_injection_client_ didFinishLoading];
 
   EXPECT_EQ(1u, GetScriptTagCount());
   ExpectConsistentContentLength();
 }